A person wants a real image of his own, 3 times enlarged. Where should he stand

⇦

⇨

A person wants a real image of his own, 3 times enlarged. Where should he stand in front of a concave mirror of radius of curvature of 30 cm?

Options

(a) 90 cm
(b) 10 cm
(c) 20 cm
(d) 30 cm

Correct Answer:

20 cm

Explanation:

Given, m = -3 and R = 30 cm

f = -(R / 2) = -15 cm

We know that, m = -(v / u) ⇒ -3 = -v / u

Therefore, v= 3u

1/f = (1/v) + (1/u) ⇒ (1/-15) = (1/3u) + (1/u) = (1+3) / 3u

-3u = 4 × 15

u = (-4 × 15) / 3

Initial position of a person, u = -20 cm

Related Questions:

1. The atomic number of the most common element in nuclear fusion is
2. Dimensions of Torque are
3. Light of frequency 8×10¹⁵ Hz is incident on a substance of photoelectric work
4. P-type semiconductors are made by adding impurity element
5. If a star converts all helium in its core to oxygen, then energy released per oxygen

Topics: Ray Optics (94)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends